Underwater acoustic sensor networks(UASNs)have problems such as low transmission reliability

high energy consumption

and long transmission delays.To address these problems

a ant colony-aided reinforcement learning opportunistic routing (ACO-RL-OR)protocol is proposed.In this protocol

firstly

a global decision function for ant colony optimization(ACO)algorithm-aided is designed

and the pheromone in the ACO algorithm and the

Q

value in reinforcement learing are combined as action strategies to determine the globally optimal route.Then

an effective reward expression is established

and the globally optimal path with the minim

um number of routing hops is found through the pheromones left by the ants on the path taken.Finally

the

Q

value is introduced into the holding time of nodes to improve the real-time performance of the protocol.Simulation results show that compared with other underwater acoustic routing protocols

the proposed protocol performs well in terms of packet delivery rate(PDR)

energy consumption

network lifetime

and end-to-end delay.